Table 1:
Characteristics of clinical trial studies included in the meta-analysis to investigate the effect of influenza vaccine on the risk of hospitalization
| First author (Reference number) | Year | Country | Sample size | Mean age | Women, % | Hypertension, % | Diabetes Mellitus, % | Smoker, % | OR (95% CI) | Duration of follow-up | Jadad Scale (Score) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Govaert (29) | 1994 | Netherlands | 1838 | 65 | - | - | - | - | 0.42 (0.24–0.74) | 5 months | 5 |
| Flucad(31) | 2008 | Finland | 658 | 60 | 26 | 67 | 20 | 18 | 0.55 (0.22 – 1.37) | 10 months | 5 |
| IVCAD (33) | 2009 | Iran | 266 | 54.7 | 33 | 83 | - | - | 1.94 (0.36 – 10.42) | 6 months | 4 |
| De Villiers (32) | 2009 | South Korea | 3242 | 69.5 | 33 | 57 | 26 | 17 | 0.91 (0.36 – 2.27) | 8 months | 5 |
| Phrommintikul (34) | 2011 | Thailand | 439 | 66 | 43 | 62 | 31 | 12 | 0.70 (0.57 – 0.82) | 24 months | 4 |
| FLUVACS (30) | 2004 | Argentina | 292 | 64.5 | 28 | 52 | 18 | 44 | 0.44 (0.28 – 0.71) | 24 months | 5 |
| Fröbert (35) | 2021 | Sweden, Denmark, Norway, Latvia, the United Kingdom, Czech Republic, Bangladesh, and Australia | 2532 | 60 | 18 | 49 | 21 | 35 | 1.38 (0.78–2.49) | 12 months | 5 |
| Loeb (28) | 2022 | India-China-Africa | 5129 | 57 | 51 | - | 23 | - | 0.83 (0.72–0.97) | 12 months | 5 |